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the key technologies that have helped US

airlines to increase their fuel efficiency by

130 percent over the past 40 years. Further

gains, these days, are generally accom-

plished in one of two ways: Planes are

either redesigned from scratch, like the

Boeing Dreamliner 787, with more aero-

dynamic airframes, lighter materials, and

better engines; or they’re upgraded with

the most efficient engine an existing air-

frame can accommodate. Careful appli-

cation of the former method yields up to

27 percent improvements in efficiency; the

latter, maybe half that.

Even so, our world of winglets doesn’t

get us far enough. Improvements to air

traffic control could also help reduce emis-

PORTION OF GREENHOUSE GAS EMISSIONS

GENERATED BY AIR TRAVEL—–A FIGURE THAT

IS EXPECTED TO GROW

_Winglets. Better engines. Lighter materials.

The airline industry is trying everything to increase

fuel efficiency and cut emissions. But the best fix

would be for us to stop flying so much.

BY

Christie Aschwanden

ILLUSTRATION BY

Jan Siemen

MOVE

Altitude

Adjustment

“WE WILL NOT HAVE TO STOP AIR TRAVEL, BUT

we will have to plan for it more carefully,”

President Nixon told the nation in Novem-

ber 1973. Schedules would be reduced, loads

increased, and the use of fuel for aviation

cut by 15 percent. Then, as now, we faced a

crisis over energy. Nixon’s speech followed

the OPEC oil shock, but concerns about the

climate were already growing. (Scientists

would begin to reach consensus on the basic

facts of global warming by decade’s end.) So

an urgent problem came to Richard Whit-

comb, a decorated NASA engineer at Lang-

ley Research Center in Virginia: Might there

be some cheap and easy way to make flying

more efficient?

In 1974, Whitcomb started playing with

an old idea—that you could gain energy effi-

ciency just by bending up the tips of airplane

wings until they were almost vertical. After

modeling the idea and testing it in wind tun-

nels, Whitcomb estimated that the “wing-

lets” he’d designed could reduce the use of

fuel by 6 to 9 percent. Real-world trials of

a Boeing 707 confirmed the lab’s success.

Whitcomb’s winglets now stand among

sions by as much as 12 percent, per a 1999

estimate from the Intergovernmental Panel

on Climate Change. But a more recent anal-

ysis suggests that we’ve accomplished half

of that already, and may not get much fur-

ther without slowing flights or compromis-

ing safety. Still, a major air traffic control

project from the Federal Aviation Admin-

istration, called NextGen, aims to imple-

ment more efficient GPS-based routes and

reduce energy-wasting traffic jams in the

air and on the tarmac.

Airplane fuel could itself be more efficient.

The aviation industry has made a lot of noise

about adopting “sustainable” fuels made

from things like algae, plant oil, food waste,

and gas captured from landfill emissions.

If You Must Fly ...

↙

Before you book, consider the carbon cost. No US domestic airline is green by any means, but

Frontier made the most efficient use of fuel in 2018—11 percent better than the industry average.

FRONTIER

SPIRIT

SOUTHWEST

SUN COUNTRY

ALASKA

UNITED

ALLEGIANT

DELTA

AMERICAN

HAWAIIAN

JET BLUE

1%

-4%

-4%

-5%

-1 2 %

1%

1%

2%

4%

4%

11%

→2.5%

LESS EFFICIENT INDUSTRY AVERAGE MORE EFFICIENT